The effect of pigment solutions on enhancing tooth bleaching efficacy: A laboratory study

To evaluate the effect of various pigments with white or blue coloring properties, which could be applied to bleached enamel surfaces, on the tooth color.

Bovine teeth, which exhibit structural characteristics closely resembling human teeth, were used. The samples were subjected to an in-office bleaching procedure using a gel containing 35% hydrogen peroxide. Color measurements were performed using a digital spectrophotometer both before and after bleaching. Subsequently, the following pigments commonly used in cosmetic and medical products were applied to the bleached enamel surfaces: blue covarine, white food dye, titanium dioxide, indigo extract, and nano-hydroxyapatite (n-HAP). Granulated coffee was used as the positive control group, and distilled water served as the negative control. Color changes were analyzed using a spectrophotometer.

The groups in which blue covarine and titanium dioxide were applied exhibited significantly lighter color values after bleaching compared to the other groups (P< 0.05). While a slight increase in whiteness was observed in the na-HAP group following bleaching, a marked darkening in color occurred in the coffee group.

Light-colored pigments, like blue covarine and titanium dioxide, support color stability after tooth bleaching and may enhance the effectiveness of the bleaching treatment by ensuring longer-lasting esthetic results.